I recently saw a photo of Gray Man author Mark Greaney on a speedboat, laptop open, typing away on a new book while rocketing across a lake somewhere.
I can relate. My guess is that he was on deadline, squeezing in a few hundred words to expand his writing day. There's an illusion that serious writers lock themselves in a cone of silence whenever they make sentences. The world never intrudes. We light a candle, pour a cup of coffee, shut the door, and enjoy a daily routine that does not deviate one iota until the book is done.